bind - DNS answer with/without authority, additional sections

dig @ns7.embarqservices.net www.126.com A +dnssec +multiline

 ; <<>> DiG 9.7.3 <<>> @ns7.embarqservices.net www.126.com A +dnssec +multiline
 ; (1 server found)
 ;; global options: +cmd
 ;; Got answer:
 ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54408
 ;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1

 ;; OPT PSEUDOSECTION:
 ; EDNS: version: 0, flags:; udp: 4096

 ;; QUESTION SECTION:
 ;www.126.com.      IN A

 ;; ANSWER SECTION:
 www.126.com.       17668 IN CNAME mcache.mail.163.com.
 mcache.mail.163.com.   269 IN CNAME email.163.com.lxdns.com.
 email.163.com.lxdns.com. 108 IN    CNAME public.mail126.001.cnccdn.com.
 public.mail126.001.cnccdn.com. 120 IN A    176.34.63.150

 ;; Query time: 1184 msec

 ;; SERVER: 207.14.235.234#53(207.14.235.234)
 ;; WHEN: Mon Apr  1 23:50:59 2013
 ;; MSG SIZE  rcvd: 160

dig @ns0.spirittelecom.com www.126.com A +dnssec +multiline

; <<>> DiG 9.7.3 <<>> @ns0.spirittelecom.com www.126.com A +dnssec +multiline
 ; (1 server found)
 ;; global options: +cmd

 ;; Got answer:
 ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57640
 ;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 5, ADDITIONAL: 6

 ;; OPT PSEUDOSECTION:
 ; EDNS: version: 0, flags:; udp: 4096
 ;; QUESTION SECTION:
 ;www.126.com.      IN A

 ;; ANSWER SECTION:

 www.126.com.       551 IN CNAME mcache.mail.163.com.
 mcache.mail.163.com.   600 IN CNAME email.163.com.lxdns.com.
 email.163.com.lxdns.com. 3599 IN CNAME public.mail126.001.cnccdn.com.
 public.mail126.001.cnccdn.com. 120 IN A    176.34.63.150

 ;; AUTHORITY SECTION:
 cnccdn.com.        146684 IN NS ns1.cnccdn.com.
 cnccdn.com.        146684 IN NS ns2.cnccdn.com.
 cnccdn.com.        146684 IN NS ns3.cnccdn.com.
 cnccdn.com.        146684 IN NS ns4.cnccdn.com.

 cnccdn.com.        146684 IN NS ns5.cnccdn.com.

 ;; ADDITIONAL SECTION:
 ns1.cnccdn.com.        146684 IN A 183.136.156.173
 ns2.cnccdn.com.        146684 IN A 122.136.46.140
 ns3.cnccdn.com.        146684 IN A 221.181.72.178
 ns4.cnccdn.com.        146684 IN A 61.54.12.67
 ns5.cnccdn.com.        146684 IN A 115.238.234.30

 ;; Query time: 889 msec

 ;; SERVER: 165.166.8.54#53(165.166.8.54)
 ;; WHEN: Mon Apr  1 23:44:57 2013
 ;; MSG SIZE  rcvd: 330

Why the first one returns QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
the second one returns QUERY: 1, ANSWER: 4, AUTHORITY: 5, ADDITIONAL: 6

One is a forwarder while the other is a resolver (recursion)?
If not what configuration differences made them behave different?

What is the 1 additional for the first query? I am not seeing the additional section.
Edit: The 1 additional is OPT pseudosetion EDNS0 I think.